Automatic clamping device for paper-cutting and other machines



July z8, 1925. 1,547,828

J,.F. SGHROETER AUTOMATIC CLAMP'ING DEVICE FOR PAPER'CUTTING AND OTHERMACHINES Filedqvxay 2 8, 1923 4 sheets-'sheet 1 l 4 ATTORNEY July 28,1925. V1,547,828

J. F. SCHROETER AUTOMATIC SLAMPING DEVICE FOR PAPER CUTTING AND'OTHERMACHINES Filed may 28. 1923 4 sheets-sheet 2 INVENTQB l E56/mom`ATT0RNEY July 28Il 1925. A E 1,547,828 J. F. SCHROEITER` lmTonuvlIccLmPIuG DEvTcE EOE PAPER CUTTING AND OTHER uAcHINEs Filed May 2. laas 4sheets-sheet gs. u w l n E g lo 7 o, I A\\\\\\\\\\\\\\ n f {ll/ l@ m ATTOR Mx/A )..mmmll//f f 5 E y Q fr w l IRSC/2me@- July z8, 1925.1,547,828

J. F. SCHROETER AUTOMATIC CLAMPING DEVICE FOR PAPER CUTTING AND OTHERMACHINES Filed May 28. 192s 4 sheets-sheet 4 q. 7 l V.'L'q al 3 i3 3 34I 31. 35 34 0 /l 32 A 1N VEN TOR .l

A TTORNEY Patented July 28, 1925.

.THN iwscnnon'r'nn.- 0F ATLANTA, GEORGIA.

AtoivIA'iI'o CLAMPING D'Evon non PAPER-CUTTING AND OTHER MACHINES.

Appncatian ined May' 2t, 1923. 'sensi Nt. 641,881.

To a'ZZ whom t may conceda:

Be it known that I, JoiiN F. SoiiiO'TEiz, a citizen of the UnitedStates, and a resident of the city of Atlanta,

State of Geoigia have invented a new 'and useful Improvement inAutomatic Clamp# ing Devices for Papei-Cutting and Other Machines,ofwhich the following is a specincation. i

The object of my invention is to provide machine of this class, or anysimilar class, wherein' a clamp' is employed for holding material on atable or other support either manually or automatically or both, andwhich will be simple in construction', easily assembled or taken do'uin`and whichv4 will be reliable in operation; This and other ob'- jects areaccomplished hy my invention, one embodiment of which is hereinaftermore particularly Vsst forth. z

For a more particular description of my invention, reference is to hevhad to the accompanying drawings-forming a part hereof, in `Which Figurel is a rear section of a paper cutter provided with my improvedIclamping mechanism, part'being vsectionally taken on the line l-1 ofFigure 2, looking in the direction' of the arrows. I Figure 2 i's asectional view taken o-n the, line of Figure l, looking in the direc'-tion of the arrows.

Figure 3 is a reduced' sectional view with parts omitted which shows theclamp in operation.

Figure 4; is a longitudinal sectional view of a portion of a pitinan, aratelnt4 and spiral ,gear and connecting' parts being shown'. f

Figure 5 is e 'sectional view taken on the line .fi-+5 of Figure 4,looking in the direction of the arrows.

Figure 6 is a sectional vieiv taken on the line 6-6 of Figure 7, lookingin the direc'` tion of the ariows.

' Figures 7 and 8 showt7 the "itman and connected parts, the tivo viewseing tal'en at right angles to each other and parts being 'shown insection. y

Figure 9 shows a second form of ratchet 'corresponding to the ratchetshov'vn in Fig# ures 4 and 5, and Figure l0 'shows a modii fiedstructure.

county of Fulton, and

lThro-uhout the variousV views' of the drawings, similarv referencecharactersdesignate similar parts.`

Where cutters are employed, or similar' instruments", .it is necessaryvto clamp the paper or other material firmly While it isv being operatedupon. The thickness of this material Will vary Within' the limits of theapparatus and in many instances it is also necessary to have either' anautomatic power clamp' which Will accommodate itself to any thicknessWithin the scope of the machine,l and ainanual clamping which will beunder the control of an operator so that the ma'-l chin'e' may be usedeither way. 'Further-A more, this machine must always be reliable andaccurate in its operation as any failure in the machine may-bedisastrous to the operator, the material or the machine. @ne embodimentof my invention Which meets these'conditionswvill now be described.

A inachine l of the type in question is provided With a table 2 carriedloy any suitable support as side frames with parts 4 above the tablewhich carry a clamp 5 and a knife' 6 in the conventional manner. Thisknifev 6 may be. driven in 'any suitable Way as lloy links 7, crank pins8 `and' cranks 9 seeuredto a'shaft 10 which may be driven by anysuitable source of po-vver, not shown, and al1 of which',ishonventional.The knife may also be guided by a diagonal link ll which causes it tomake a shear out. i

Of course, the knife mechanism may be Varied, as desired andmodifications are not shown, as all such structures are old and 'Wellknown in the art and form no part of this invention. It may be that apunch may be substituted for the knife in which case there would be nodraw cut. These or any other desired devices may be used, as Will beunderstood, without fui-ther reference or description.

The' clamp 5 is actuated by mechanism lwhich w'ilinow be described. Inthe enibodinient shown this eianip is secured ai each end to racks 12which mesh With segmental gears lswhieh are fixed to a shaft 14 and thisshaft is 'surrounded in part by ai coil spring' l5 which has one end Xedin the gear 13 andthe other 'end is fixed in a Hangs 1'6 which dependsfrom thetable This spring acts'as acounterweight so as body 37. soas notEil Cil

to keep the clamp raised under normal conditions, and when this clamp islowered to 'lunction as a clamp in a manner which will' be describedbelow, this spring 15 is in tension with suiiicient power to raise theclamp whenever 'the lowering mechanism is released. lf desired, acounterweight could be substituted tor this spring 15, as is obvious.

At one end, orany other convenient location, the shaft 14 is providedwith a sprocket wheel 17 which carriesa sprocket chain 18 which runsover an idle sprocket wheel 19 mounted on a stud shaft 20 which extendsfrom one of the supports 3 and from the wheel 19 the chain 1S runs to asegmental sprocket wheel 21 fixed on the pedal shaft 22, which ispivotally mounted in the pedes tais 3 of the machine. This shaft 22carries a toot pedal 23 of the conventional kind. Normally this tootpedal is kept raised by a suitable spring 24 mounted 0n the stud shaft2O and secured at one end to a frame l3 and at the other to the wheel19. `When the toot pedal 23 is depressed the tension of this spring24 isovercome and also the tension ot the spring 15 and the shaft 14 isturned so as to drive the segmental gears 13 which in turn lower theracks 12 and cause the clamp 5 to Vfunction on any material 25 that maybe placed on the table 2.

@ne segmental gear 13 has curved arms 26 spaced at any convenientdistance apart, and one of these arms is extended at 27 to engage a stop23 on a side frame 3 so as to limit the upward movement of the clamp 5.Both of these arms have a suitable pivotal connection b29 with the arms30 of a yoke 31 which is composed of these arms and a con necting shaft32. Between the arms 30 the shaft 32 passes through a bearing 33 whichforms an integral part of a member 34 which has a collar 35 and aplunger 36. The plunger extends into a cylinder or body 37 and thecollar 35 normally rests on a washer 33 which is sandwiched in betweenthis collar and the body 37 and just above the to rest thereon, but itdoes rest on the top of a sleeve 39. This sleeve is preferably made intwo parts which are held in proper relation by means of clamping bolts40 with nuts 41 which may be adjusted thereon so as to put more or lesspressure on the tension springs 42 which yare placed on said bolts. Tomaintain a proper connection between the body 37 and the sleeve 39, lprovide a suitable lining A43 oi leather or any other suitable material,which is preferably put in a recess formed for the purpose so that itwill lie true and remain true at all times. This sleeve is alsoprovi-ded with two sets of guides at right angles to each other. One set44 permits the pivots 29 to slide 'freely therein and the other setreceives the spiral racks 45 which move freely therein and are kept inplace by the cover plates 46 which are held by screws 47 or any othersuitable means. The lower end of the sleeve 39 rests on a suitable iibrewasher 48 which rests on a hardened steel washer 49 and both of thesesurround the reduced lower end of the body 37 and the lower washer 49rests on a spiral gear 50 which engages the spiral rack bars 45 and isturned by them as it rises and falls in a manner which will be describedbelow. It' desired, the washers 48 and 49 may bereplaced by a ballbearing or a roller bearing. The'lower end of the spiral gear 50 has apawl and ratchet connection 51 with the body 37. ln the embodiment of myinvention shown yin Figures 4 and 5 the body 3T has spring pressed pawls52 extending in opposite directions along the same diameter so as toengage the teeth 53 which are fixed so as to proJect inwardly into arecess at the bottom of the gear 50. rlhese ratchet teeth are preferablygiven an odd number so that one of the pawls 52 will be in engagementwith the teeth twice as often as they would be in engagement if an evennumber of teeth were employed. ln Figure 9 is shown an ordinary rollerratchet 54 with springs 55 to force the rollers into engagement with thesmooth interior 56 which takes the place ofthe teeth 53. The advantageof this ratchet is that it will instantly engage at any point and permitno lost motion of any kind whatsoever and so this is the preferredembodiment of my invention. However, while I have shown two ratchets, itis obvious that` any suitable form of ratchet may be employed.

The lower end of thevbody 37 and the lower end oi' the spiral gear 50are closed by means of a suitable cover plate 57 which is securedV tothe body 37 by screws 58, ork

other suitable means, so as to conceal and protectthe ratchet 51 with aworking joint and this cover plate 57 has a conical collar 59 whichenters corresponding recess in the bottom of the spiral gear 50 so thaton the return movement this spiral gear when turned by the rack bars 45rwill not turn too freely on the body. l

The spiral racks 45 slide freely in the recesses under the cover plates46, as above stated, and they are provided at their upper ends with stoppins 60 which prevent ya separation of these rack bars 45 Jfrom thesleeve 39 as might occur when the clamp is manually operated, asdescribed above, if these pins were omitted. The lower ends vof these rak bars 45 are secured to a bearing 61 which engages a Vcrank pin 62 on agear 63 which is mounted on a stud shaft 64 which extends from a Vtraine3 and this gear 63 meshes with a gear 65 with the same number of teethwhich is iixed to the main shaft 10 of the machine. O1 course, this isonly one Vsleeve 39 and then the y'resistance due tothe way of drivingthe pitman 66 which connects .the crank pin 62 with the yoke `3l whichhas been Any other suitable mechanism lmay be used for driving. It isessential that it be driven so as to elongate and contract in a mannerwhich will be described below, and provided this occursit. may beconnected and driven in any suitable manner.

In the embodiment of my invention shown in Figure l0 the pitman '66 isdriven by an eccentric 67 on the main shaft l0 and the yoke 3l drives abell crank lever 68 mounted on a rocker shaft 69 and this lever driveslinks'70 that runs to arms 26 ofthe gears 13 through which the racks l2are driven as above described. Y

Operation.

In view of the foregoing, the4 operation'of my improved clamp will bereadily understood. vIf the operator wishesv rst fto bring the clamp,down on the. material to be clamped by manual effort, he depresses thefoot pedal 23 in the conventional manner and then the sprocket chain 18functions so as to draw theclamp down on the work, as above described.The operator thenapplies power in the usual manner and the shaft l0 isdriven and brings -down .the knife through the connections abovedescribed and simultaneously drives the gears VV and 63 and the greater,to raise this greater part until the shoulder 35 and washer 38 of the`plunger rest lon the material 25 is encountered and as lsoon-as thisresistance is encountered the spiral racks 45 begin to turn-the spiralgear. 50 thereby 'causing' frictionbetween the leather 43 in the sleeve39 and the body 37'w-hich isproportional to the tension ofthe springs42which is imposed by the nuts 4l and may be whatever is desirableforproperv clamping. This permits a proper pressure of the clamp for anythickness of material, the lost motion being taken up by the spiralracks 4:5 and theA frictional engagement above mentioned, and thiscontinues until the limit to the stroke is reached, it being understoodthat the body 37 must turn because it is positively driven from the gear50 through the ratchet 5l. As soon as the limit of the movement of thepitman 66 is reached and that is as soon as the knife 6 has finishedlcutting or operating, the pitman begins its reverse movement and theinstant it starts to reverse the knife 6 rises also andthe clamp 5 risesunder the inuence of the spring 15 while the pitman releases at theratchet 51 and allows the racks to turn the spiral 50 on the returnmovement without in any way turning the body 37 andas this turningoccurs, the only resistance to the turning ofthe gear 50 is the vconicalVcollar 59 secured in the' cover 57 which is.

described in detail above.v

part of thepitman 66 so asl fixed vto the Vbody 237 sothat during thereturn movement, the pitman 66 assumes its most extended position andthen when its movement is finished the automatic mechanism which isgenerally employed in such machines brings both .the clamp andthe knifetoy rest and' the clamp rests at the upper limit of its movement,` asdetermined bythe position of the stop 38. It is apparent that theresistance of the spiral gear to its reverse movement causes aresistance to an elongation of the.A pitman 66 and vthis resistancecauses additional stresses on the parts 31 and 62 connected to thepitman and soremoves apart or all of the clamp lifting loadfrom vthespring l5 to the crankipin 62 so that if desired, by tightening thescrews 58 and making the plunger 36 tight in the body 37, the spring l5may be dispensed with. Of course, this limit should be below Vthe Vloweredge of the knife which should never be in a position to cut the hand ofthe operator.v

That/mit 8yst`em.`,

Inthe foregoing has been described some automatic devices including thepitman-for a cutting' machine. These are suitable for small machines,say i thirty-two? Ainch machines. "Where machines are larger, as forty,fifty, or ninety or onehundred and twentyeight inch machines, it isobvious that thev clamp must be operatedwith more clamping power andthen' it is necessary, to employ onev or more pitmans, all of which maybe connected in any suitable manner, as in duplication-ofthe mannershown, so that 'this invention can be and it is not infany. wayv limitedtothe prev cise connectionsjherein shown and described, nor is itlimited in any way to the precise form` herein shown and described, butis broad enough to come within the scope of the annexed. claims.

Having thus described my invention, what I claim is:

l. Ina machine of the class described, a table, a clamp adapted tohold asubstance ontheKt-able and means for actuating said clamp including inits construction a spiral gear device which shortcns and el-ongateswhile functioning and has vparts in frictional engagement while'clamping and free while releasing. y 2. In a.machinelofthev classdescribed,i a table, -a clampy adapted. to hold a substance against saidtable and mechanism'for vactuating said clamp 'automaticallyembodying in"its construction a pitman which shortens cover all structures that ytable, a clamp adapted tov force a eating parts,

and elongates while functioning and clamps itself so as to be nearlyrigid vwhile shortening and releases while elongating.

3. In a machine of the classdescribed, a table adapted to hold asubstance and a clamp adapted to force the substance against the tableand means for actuating said clamp embodying in its construction apitman which moves in two directions and is provided with reciprocatingand rotating parts which are adapted to function so as to clamp while onone movement and torelease while on the other movement.

. a. In a machine of the class described, a substance against said tableand holdthe same and means for actuating said clamp embodying in itsconstruction a pitman with reciprorotary rparts and frictional parts,these three vparts .being so arranged and disposed that thepitmanlfunctions while clamping with a force proportional t-o thefrictional resistance of the parts and freely releases when notclamping.

5. In a machine of the class described, a table, a clamp adapted to holdva substance on the table and means including'a pitman moving in twodirections for actuating said Gil y clamp, such pitman being providedwith elatively movable partsV which engage with frictional contact whilemoving in one direc tion'and while the clamp Yis clampingA and withoutsuch contact whenV moving in the other direction, thus allowing' a freerelease of the clamp when not functioning as a clamp. Y

QIn a machineof the class described, a table, a clamp adapted to hold asubstance on the table, means including a pitman moving in twodirections k'for actuating said clamp, such pitman being provided withrelatively movable parts which engage with frictional contact whilemoving in one direction and while the clamp is clamping and without suchcontact .when moving in the otherdirection, thus allowing a free releaseof the clamp when not functioning as a clamp and manually controlledmeans for actuating the clamp and releasing the same from the firstmentioned means'while acta.V ated by the manually controlled means.

7. In a machine of table, a clamp adapted to khold a substance Lon thetable and means for actuating said clamp including in its construction apitman which shortens and elongates while functioning and has parts infrictional engage-` ment while clamping and free while releasing, one ofsaid frictional parts of said pitman being provided with a spiral gearwith Y a ratchet connected thereto, saidgear being driven by at leastone'corresponding rack which also forms apart of the pitman.

8. In a machine of the class described, a

' table, a clamp adapted to hold a substance the class described,`a

von the'table and means for actuating said sleeve with a suitablefrictional surface such.

as leather, a body with va second surface engaging said frictionalsurface, a spiral gear connected to said body with a ratchetconnectionand means for rot-ating said spiral gear.

9. In a machine of thevclass described,'a table, a clamp adapted tokhold a substance onthe table and means for actuating said clampincluding in its construction a device which shortens kand elongateswhile functioning and has parts in frictional engagement while clampingandkfree while releasing, said parts having YKspring controlled meanssubject to adjustment, whereby the tension of the clamping means maybevaried 7ithin limits, Vas desired, by varying the pressure of'thefrictional contact ofA said partsv and means for causing one of saidparts to move with regard to the other while the clamp is functioningand means for permitting a free release from such driving means when theclamp isnot functioning.

10. In a machine ofthe class described, a

table, a clamp adapted to hold a substance eans vfor actuating said ing.mechanism so ,thatY when the clamp is driven by other means than theactuating means above mentioned, this plunger may shift Vwithout causingsuch actuating means to function.V f

11. Ina machine of the class described, atable, a clampadapted Vto holda substance on the table, means for actuating Ysaid clamp `including inits construction a spiral device which shortens and elongates whilefunctioning'and has parts in frictional engagement while clamping andfree while releasing kand a stop for llimiting the upward movement ofsaid clamp upon releasing.

12. In a machine of the class described, a pitman'providedl with one ormore spiral rack bars, a spiral gear engaging said bar or bars, aratchet connected to said spiral gear, a frictional body driven by saidratchet in said spiral, a sleeve with a frictional surface engaging saidbody and also said rack or racks and means forV connecting said bodywith mechanism to'be driven. v l V13. In a machine oflthe classdescribed, a pitman comprising one or more spiral rack bars, a spiralgear driven by said bar or bars, a body having a ratchet connection Withsaid spiral gear, a sleeve With a frictional surface engaging said bodyand also said bar or bars, means for varying the pressure of saidfrictional parts and means for connecting' said body With mechanism tobe driven by the pitman.

14. In a machine of the class described, a pitman provided With one ormore spiral racks, a spiral gear engaging said rack or racks, a bodyconnected to said spiral gear by means of a ratchet connection, a sleeveWith a frictional surface engaging said body and also said rack orracks, a plunger adapted to move in said body, a yoke With dependingarms pivotally mounted in said plunger and driven mechanism connectedWith said yoke, said driven mechanism forming also a guide for said yokeand one end of the pitman. v

l5. In a machine ofthe class described, a table, a clamp adapted to holda substance on the table and means for actuating said clamp including inits construction a spiral device to be' used in multiple units Whichshortens and elongates While functioning and has parts in frictionalengagement While clamping and'free While releasing.

In testimony whereof, I have hereunto set my hand this 25th day of May,1923.

JOHN F. SCHROETER.'

